Impact- and Thermal-Resistant Epoxy Resin Toughened with Acacia Honey

Ivana Stajcic; Filip Veljkovic; Milos Petrovic; Suzana Veličkovic; Vesna Radojevic; Branislav Vlahović; Aleksandar Stajcic

doi:10.3390/polym15102261

Impact- and Thermal-Resistant Epoxy Resin Toughened with Acacia Honey

Polymers (Basel). 2023 May 10;15(10):2261. doi: 10.3390/polym15102261.

Authors

Ivana Stajcic¹, Filip Veljkovic¹, Milos Petrovic², Suzana Veličkovic¹, Vesna Radojevic², Branislav Vlahović³, Aleksandar Stajcic⁴

Affiliations

¹ Department of Physical Chemistry, "Vinča" Institute of Nuclear Sciences-National Institute of the Republic of Serbia, University of Belgrade, Mike Petrovića Alasa 12-14, P.O. Box 522, 11001 Belgrade, Serbia.
² Faculty of Technology and Metallurgy, University of Belgrade, 11000 Belgrade, Serbia.
³ Mathematics and Physics Department, North Carolina Central University, Durham, NC 27707, USA.
⁴ Center for Microelectronic Technologies, Institute of Chemistry, Technology and Metallurgy-National Institute of the Republic of Serbia, University of Belgrade, 11000 Belgrade, Serbia.

Abstract

High performance polymers with bio-based modifiers are promising materials in terms of applications and environmental impact. In this work, raw acacia honey was used as a bio-modifier for epoxy resin, as a rich source of functional groups. The addition of honey resulted in the formation of highly stable structures that were observed in scanning electron microscopy images as separate phases at the fracture surface, which were involved in the toughening of the resin. Structural changes were investigated, revealing the formation of a new aldehyde carbonyl group. Thermal analysis confirmed the formation of products that were stable up to 600 °C, with a glass transition temperature of 228 °C. An energy-controlled impact test was performed to compare the absorbed impact energy of bio-modified epoxy containing different amounts of honey with unmodified epoxy resin. The results showed that bio-modified epoxy resin with 3 wt% of acacia honey could withstand several impacts with full recovery, while unmodified epoxy resin broke at first impact. The absorbed energy at first impact was 2.5 times higher for bio-modified epoxy resin than it was for unmodified epoxy resin. In this manner, by using simple preparation and a raw material that is abundant in nature, a novel epoxy with high thermal and impact resistance was obtained, opening a path for further research in this field.

Keywords: acacia honey; bio-modifier; epoxy resin; impact-resistant; thermal stability.

Grants and funding

This work was financially supported by the North Carolina Central University, USA, NSF DMR EiR 2101041, NSF DMR PREM 2122044, and DOE/NNSA NA0003979 awards and Ministry of Education, Science and Technological Development of the Republic of Serbia (Grant Nos. 451-03-47/2023-01/200017 and 451-03-47/2023-01/200026).